Remove unnecessary space in error message.

RELNOTES: None
PiperOrigin-RevId: 188341095

src/main/java/com/google/devtools/build/lib/bazel/rules/android/AndroidSdkRepositoryFunction.java

@@ -105,7 +105,7 @@ public RepositoryDirectoryValue.Builder fetch(
           new EvalException(
               rule.getLocation(),
               "Either the path attribute of android_sdk_repository or the ANDROID_HOME environment "
-                  + " variable must be set."),
+                  + "variable must be set."),
           Transience.PERSISTENT);
     }